The "other" interactive editor that's commonly used is Emacs. Emacs
actually refers to a family of editors; versions of Emacs run under
almost any operating system available. However, the most important
(and most commonly used) version of Emacs is
"GNU Emacs,"
developed by the Free Software Foundation.

GNU Emacs is popular because it's the most powerful editor in the
Emacs family; it is also available for free, under the terms of the
FSF's General Public License. (You can also get it from the Power Tools
disc.) Although there are certainly
religious differences between Emacs users and
vi
users, most
people agree that Emacs provides a much more powerful and richer
working environment.

What's so good about Emacs, aside from the fact that it's free? There
are any number of individual features that I could mention. (I'll
give a list of favorite features in article
32.2
.)
In a word, though, the best feature of Emacs is the extent to which it
interacts with other UNIX features. For example, it has a built-in
email (
1.33
)
system so you can send and receive mail without leaving the
editor. It has tools for "editing" (deleting, copying, renaming)
files, for running a UNIX shell within Emacs, and so on. The C shell
has a rather awkward command history mechanism; the Korn shell has
something more elaborate. But imagine being able to recall and edit
your commands as easily as you edit a letter!
That's far beyond the
abilities of any shell, but it's simple when you run a shell inside
your editor.

In this book, we can't give anywhere near as much attention to Emacs
as we can to
vi
(
30.1
)
,
but we will point out some of its best features
and a few tricks that will help you get the most out of it.